Thousands of South American Indians were infected with measles, killing hundreds, so that United States scientists could study the effects on primitive societies of natural selection, according to a book due to be published next week.

The story of genetic research on humans, which took 10 years to uncover, is likely to shake the world of anthropology to its core, according to Professor Terry Turner of Cornell University, who has read the proofs. "In its scale, ramifications and sheer criminality and corruption it is unparalleled in the history of anthropology," Prof Turner says in a warning letter to Louise Lamphere, the president of the American Anthropology Association (AAA).

The book accuses James Neel, the geneticist who headed a long-term project to study the Yanomami people of Venezuela in the mid-60s, of using a virulent measles vaccine to spark an epidemic that killed hundreds and probably thousands. Once the epidemic was under way, says the book, the research team "refused to provide any medical assistance to the sick and dying Yanomami, on explicit order from Neel. He insisted to his colleagues that they were only there to observe and record the epidemic, and that they must stick strictly to their roles as scientists, not provide medical help".

Darkness In El Dorado, by the investigative journalist Patrick Tierney, is due to be published on October 1. Prof Turner, whose letter was co-signed by fellow anthropologist Leslie Sponsel of the University of Hawaii, was trying to warn the AAA of the impending scandal so the profession could defend itself. Although Neel died last February, many of his associates, including authors of classic anthropology texts, are still alive.

The accusations will be aired at the AAA's annual meeting in November, when scientists have been invited to defend their work. None has commented publicly, but they are asking colleagues to come to their defense.

One of the most controversial aspects of the research that allegedly culminated in the epidemic is that it was funded by the US atomic energy commission, which was anxious to discover what might happen to communities when large numbers were wiped out by nuclear war.

While there are no texts or recorded speeches by Neel explaining his conduct, Prof Turner believes the only explanation is that he was trying to test controversial eugenic theories like the Nazi scientist Josef Mengele.

He quotes another anthropologist who read the manuscript as saying: "Mr Tierney's analysis is a case study of the dangers in science of the uncontrolled ego, of lack of respect for life, and of greed and self-indulgence. It is a further extraordinary revelation of malicious and perverted work conducted under the aegis of the atomic energy commission."

Prof Turner says Neel and his group used a virulent vaccine called Edmonson B on the Yanomami. It was known to produce symptoms virtually indistinguishable from cases of measles. "There is no record that Neel sought any medical advice before applying the vaccine. He never informed the appropriate organs of the Venezuelan government that his group was planning to carry out a vaccination campaign, as he was legally required to do."

Prof Turner says that Neel thought that "natural" human society, before the advent of large-scale agriculture, consists of small, isolated groups in which dominant genes -- specifically a gene he believed existed for "leadership" or "innate ability" -- have a selective advantage. Male carriers of this gene would gain access to a disproportionate total of females, reproducing their genes more frequently than less "innately able" males. The result is continual upgrading of the human genetic stock.

He says Neel believed that in modern societies superior leadership genes would be swamped by mass genetic mediocrity.

"The political implication of this fascistic eugenics is clearly that society should be reorganised into small breeding isolates in which genetically superior males could emerge into dominance, eliminating or subordinating the male losers in the competition for leadership and women, and amassing harems of brood females," Prof Turner adds.

In the memo he says: "One of Tierney's more startling revelations is that the whole Yanomami project was an outgrowth and continuation of the atomic energy commission's secret programme of experiments on human subjects." Neel was part of the medical and genetic research team attached to the atomic energy commission since the days of the Manhattan Project. Well-known for his research into the effects of radiation on humans, Neel led the team that investigated the effects of the Hiroshima and Nagasaki bombs on survivors and their children.

According to Prof Turner, the same group secretly carried out experiments on humans in the US. These included injecting people with radioactive plutonium without their knowledge.

"This nightmarish story -- a real anthropological heart of darkness beyond the imagining of even a Joseph Conrad (though not, perhaps, a Josef Mengele) -- will be seen (rightly in our view) by the public, as well as most anthropologists, as putting the whole discipline on trial," he says.

"This book should . . . cause the field to understand how the corrupt and depraved protagonists could have spread their poison for so long while they were accorded great respect throughout the Western world . . . This should never be allowed to happen again."

In a statement, the AAA said it was "extremely concerned" about the allegations. "If proven true they would constitute a serious violation of Yanomami human rights and our code of ethics . . . The association is anticipating conducting an open forum during our annual meeting to provide an opportunity for our members to review and discuss the issues and allegations raised in the book."